For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningCompass
The vehicle may have a compass display in the Driver Information Center (DIC).
The compass receives its heading and other information from the Global Positioning
System (GPS) antenna, StabiliTrak, and vehicle speed information.
Avoid covering the GPS antenna, located on the roof, for long perio ...
Vehicle Access
Specifications
Door Lock/Indicator Schematics
Door Control Module Schematics
Release Systems Schematics
Fuel Tank Filler Door Lock Actuator Replacement
Preliminary Procedure
Remove the fuel tank filler housing. Refer to Fuel Tank Filler Pipe Housing ...
Interior Windnoise
Warning: Refer to Assistant Driving Warning in the Preface section.
Interior windnoise is not heard when the window is lowered. Interior
windnoise is caused by the air leaving the inside of the vehicle
through a seal or a seam.
Tape over the relief valves to cause added air pressure wi ...